Generally, in a liquid crystal display, liquid crystal is injected between two substrates on which electrodes are formed, and the amount of voltage that is applied to the electrodes is controlled to adjust the amount of transmitted light.
The liquid crystal molecules have the anisotropic property, and the anisotropic property of liquid cells or films that include the molecules depends on how the liquid crystal molecules are distributed and an inclination angle of the molecules in respect to the substrate. Accordingly, in the case of the liquid crystal display, the amount and the color of light depends on the viewing angle.
Since the most liquid crystal molecules have the positive retardation in a thickness direction of the liquid crystal display surface, it is required that retardation compensator which has almost the same birefringence as the liquid crystal and the negative retardation is used to compensate the viewing angle.
In order to produce the retardation compensator that has the negative retardation in the thickness direction, 1) a process of stretching a film, and 2) a process of applying a substance having the birefringence are used. Currently, most retardation compensator is produced using the stretching process. However, since a stretching ratio is mechanically controlled, it is not easy to desirably control the angle, and the polarizing plates must be attached one by one while rolls are not used during the attachment by means of the polarizing plates. Accordingly, efficiency of the process is poor and it is difficult to control impurities.
Therefore, in order to avoid the above-mentioned disadvantages, a process of applying a substance having the birefringence on a surface of a film to produce a compensator is suggested. Korean Patent Application No. 10-2005-4439 discloses a process of applying liquid crystal having the birefringence. However, since the birefringence of the liquid crystal is very high, the retardation of the compensator is significantly changed even though the alignment of the liquid crystal and the thickness of the coat are slightly changed. Accordingly, it is difficult to control the retardation. In addition, as the area of the display is increased, it is difficult to ensure the clear color.